A library apparatus is well-known as a high capacity external storage device that is connected with a large scale computer. The library apparatus includes a plurality of cartridges, and each of the cartridges stores a tape medium. And the library apparatus moves the cartridge to a tape drive unit by a movement unit such as an accessor or a robot and writes data into or reads data from the tape medium by the tape drive unit. Recently, there is a library apparatus including a plurality of tape drive units or a library apparatus including an optical disk drive unit.
A minimum system of the library apparatus is a library apparatus that includes one tape drive unit that is arranged in a rack space of 1U (44.45 mm) in height. FIGS. 1A to 1C illustrate a perspective view of a conventional library apparatus 9. FIG. 1A illustrates a perspective view of a library apparatus 9 having 1U in height viewed from a front panel 9F side. The front panel 9F includes an operator panel 9P and an opening for a magazine 9M that stores the cartridges. The operator panel 9P includes an operation button 9B and a display unit 9D. The front panel 9F has ear portions 9E extending on both sides, and each of the ear portions 9E has a fixing hole 9H. The library apparatus 9 includes a rear panel (not illustrated) which includes a power receptacle, a power switch and a connector for communication with an external device.
FIG. 1B illustrates a method for mounting and fixing the library apparatus 9 illustrated in FIG. 1A in a rack 8. The rack 8 is a rack of 19 inch size which is a universal pitch of the EIAJ or EIA standard, and a prop of the rack 8 has L-shaped cross-section. The front panel 9F of the library apparatus 9 is fixed to a rack 8 with a screw through the fixing hole 9H formed on the ear portion 9E. Moreover, a back portion of the library apparatus 9 is fixed to the rack 8 with a screw 9S using a L-shaped metal fitting 9L as illustrated in FIG. 1C. When a slide rail is provided on the rack 8, the library apparatus 9 is mounted on the slide rail.
When the cartridge stored in the library apparatus 9 is replaced, the cartridge is not replaced one by one, but it is performed to replace a magazine that stores a plurality of the cartridges (For instance, refer to Japanese Laid-open Patent Publication No. 2003-115146). On the other hand, only one magazine 9M is arranged in the library apparatus 9 of 1U in height illustrated in FIG. 1A.
FIG. 2A illustrates an internal structure of the library apparatus 9 illustrated in FIG. 1A, and there is a front panel 9F at the left side in FIG. 2A. The magazine 4 inserted into the library apparatus 9 includes five columns 4C1 to 4C5 in the longitudinal direction (in depth direction) of the magazine 4, and there is space for storing two cartridges 10 in each of columns. This space stores two cartridges 10 in the short side direction (in width direction) of the magazine 4, and a portion where each cartridge 10 is stored is called a slot. Therefore, there are ten slots 4S1 to 4S10 in the magazine 4 inserted in the library apparatus 9. However, since the nearest slot 4S9 to the front panel 9F is a retraction slot, the magazine 4 of the library apparatus 9 stores nine cartridges 10 that is the maximum number of the cartridges.
Moreover, a tape drive unit 1 for recording or reproducing the cartridge 10 is located adjacent to the opposite end of the front panel 9F of the library apparatus 9. Moreover, the rail 6 is provided along in the longitudinal direction of the magazine 4 in the space beside the magazine 4 in the library apparatus 9, and the robot 7 that is the movement unit moves on this rail 6. The robot 7 selects the cartridges 10, which is recorded or reproduced by the tape drive unit 1, from either of the columns 4C1 to 4C5 of magazine 4 and moves it to the tape drive unit 1. FIG. 2A omits illustration of a power supply unit and a control unit.
In this housing, the robot 7 takes out directly the cartridge 10 stored in the slots 4S2, 4S4, 4S6, 4S8 and 4S10 which are adjacent to the rail 6, and the robot 7 moves the cartridge 10 to the tape drive 1. On the other hand, the robot 7 cannot take out directly the cartridge 10 stored in the slots 4S1, 4S3, 4S5 and 4S7 on the side far from the rail 6. When the cartridge 10 stored in the slots 4S1, 4S3, 4S5, and 4S7 is moved to the tape drive 1, the retraction slot 4S9 is used.
Hereinafter, an example that the No. 5 cartridge 10 stored in the slot 4S5 is moved to the tape drive unit 1 is described. In this housing, first of all, as the robot 7 takes out the No. 9 cartridge 10 stored in the slot 4S10 and stores into the retraction slot 4S9 to empty the slot 4S10. Next, the robot 7 takes out the No. 6 cartridge 10 from the slot 4S6, and moves the cartridge 10 to the empty slot 4S10. After this operation, the robot 7 takes out the No. 5 cartridge 10 stored in the slot 4S5 in the column 4C3, and moves it to the tape drive unit 1.
FIG. 2B illustrates an example of the cartridge 10 used in the library apparatus 9. The cartridge 10 used in the library apparatus 9 is called LTO (Linear Tape Open) cartridge. And the cartridge 10 has a structure that a magnetic tape 13 is pulled out from an opening 12 by a leader pin 14. The opening 12 is provided on the side of the cartridge 10. The cartridge 10 has a storage capacity of between 100 GB and 800 GB, depending on a specification. Besides the opening 12, there are an identification label sticking area 11 and a recess 15 on the side of the cartridge 10. The recess 15 is provided to be inserted by a picker of the robot 7 described later. The bar code label on which the bar code is printed, for instance, is stuck on the identification label sticking area 11. Moreover, a reel for winding the magnetic tape 13 is exposed on the bottom of the cartridge 10.
Japanese Laid-open Patent Publication No. 2003-115146 is an example of conventional technique.
However, in the library apparatus of 1U in height illustrated in FIG. 2A, the magazine and the movement area of the robot are deposited in an area other than the tape drive, the power supply unit and the control unit. Since the cartridges are not stored in the movement area of the robot, the storage efficiency of the cartridges is bad. That is, the maximum storage volumes of the cartridges in the library apparatus of 1U in height illustrated in FIG. 2A are nine volumes.